1. Technical Field
The present invention relates to liquid ejection methods and liquid ejection apparatuses.
2. Related Art
Inkjet printers are known in which a head is moved in a movement direction and a printed image is accomplished by causing ink to be ejected from nozzles during that movement.
In these printers, sometimes the ink droplets do not land in the correct position on the medium due to problems such as the processing precision of the nozzles. When this happens, shading variations occur in the vicinity of the region in which the ink droplets should have landed and stripe shaped density irregularities are produced in the printed image.
Accordingly, methods have been proposed to remedy these density irregularities by sampling an image using a CCD sensor and correcting the data to be outputted by the inkjet printer based on gain irregularity characteristics of the CCD sensor (See JP-A-2-54676).
Other methods are also proposed in which density irregularity test patterns are printed and density irregularity correction is carried out based on density data of the density irregularity test patterns (See JP-A-6-166247).
If a faulty nozzle, which cannot perform ejection when ink droplets should be ejected, occurs during printing, dots will not be formed in positions where the intended dots should have been formed. In this case, density irregularities will be produced in the printed image even if correction had been carried out of density irregularities due to problems such as the processing precision of the nozzles.
Also, although the faulty nozzle may be recovered by cleaning the nozzle face, the printing time will be lengthened by the time required for cleaning.